3D printing technologies that have recently started to receive attention have enhanced in degree of freedom with respect to a configuration of a product because a mold required in a typical mass production manner is not necessary at all, and also constraint conditions needed for molding the product in the mold are removed. For example, when a product is produced by using injection molding, in order to extract the product from a mold, the product needs to have no undercut and have a predetermined draft angle. Also, a spatially complicated shape of the product is one of limitations that may not be achieved by the mold.
However, the 3D printing technologies may enable a component, which has a shape that is impossible to be molded in the mass production manner using the mold, to be molded and also mold a component even in an assembled state. Thus, components having various conditions may be built.
Like this, the 3D printing technologies have brought radical change in approach to the shape of the product and production of the product to almost resolve difficulties when manufacturing a mock-up or prototype.
The 3D printing technologies may be classified into a photocuring process, a sintering process, a fused deposition modeling (FDM) manner, a color jetting printing manner, a multi jetting printing or polyjet manner in which the photocuring process is mixed with the color jetting printing manner, and a thin film laminating manner (LOM, PLT, PSL) according to the processes.
Also, sources used for the 3D printing technologies may be classified into a solid phase, a liquid phase, and a powder type according to phases of the sources. In detail, the solid phase source is mainly used for the FDM printing apparatus. Poly lactic acid (PLA), acrylonitrile-butadiene-styrene (ABS) resin, and styrene which are thermo-plastic resins are used as main materials of the solid phase source and are processed in a filament form.
Also, the liquid phase source is a gel type source and mainly used for the photocuring process. The power type source is used for a printing apparatus using a selective laser sintering (SLS) manner that is one of a sintering manner. Here, power type polymer or a metal source sintered by a laser is a main material of the power type source.
In case of the 3D printing apparatus using the color jetting printing manner or polyjet manner, since a liquid source (hereinafter, referred to as an “ink”) is sprayed through a nozzle of a printing head, the ink may be formed on a nozzle tip. Also, the ink formed on the nozzle tip may be hardened or cured by UV light reflected from a curing lamp to block the nozzle. Particularly, when the ink formed on the nozzle tip is cured by the UV light that is reflected from the UV lamp, the printing head itself has to be replaced.
Also, the head for the 3D printing apparatus is very expensive. Also, since the ink has very high viscosity, the printing head may be damaged. Thus, it may be necessary to provide a strong cleaning unit for cleanly cleaning the nozzle of the printing head after the printing is completed, before the printing starts, or after a long resting state.
In case of the 3D printing apparatus using the typical inkjet manner, which is disclosed in US Patent Registration No. 7744364, a blade for wiping a nozzle is provided to clean a nozzle tip of the printing head.
However, in case of the nozzle cleaning mechanism according to the related art, it may be difficult to completely remove an ink remaining on the inside of the printing head and an ink attached to the nozzle tip.